<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button id="button">button</button><br>
    <ul id="container"></ul>
    <script>
        document.getElementById('button').addEventListener('click',function(){
        // 记录任务开始时间
        let now = Date.now();
        // 插入一万条数据
        const total = 10000;
        // 获取容器
        let ul = document.getElementById('container');
        // 将数据插入容器中
        for (let i = 0; i < total; i++) {
            let li = document.createElement('li');
            li.innerText = ~~(Math.random() * total)
            ul.appendChild(li);
        }
        console.log('JS运行时间：',Date.now() - now);
        setTimeout(()=>{
        console.log('总运行时间：',Date.now() - now);
        },0)

        // print JS运行时间：38
        // print 总运行时间：957
    })
    </script>    
</body>
</html>